I owned you Linkman!
Dunno really about the cheat applications... maybe you could store the played time and collected objects too and do a calculation when a score is about to be submitted. And only if it matches the score will be sent. Of course if people knew about this they would still be able to change the time / items accordinly, but at least it would be way harder to do.
Maybe smb else has a better idea.
I have a request: I want to be able to change the spaceship sprite.
So that you can put a PNG with the matching size in a subfolder of the game and ingame you can select which version you want. Actually it's fairly easy to do, but I somehow doubt you're interested in such a feature. Don't be so cruel and stand between me and my penis-shaped spaceship!